Apparatus for forwarding the warp in a weaving machine



y 1966 SHIGEO ISHIOKA 3,249,125

APPARATUS FOR FORWARDING THE WARP IN A WEAVING MACHINE Filed June 16, 1964 4 Sheets-Sheet 1 I NVEN TOR.

S H/ 452 0 fsx o g May 3, 1966 SHIGEO ISHIOKA APPARATUS FOR FORWARDING THE WARP IN A WEAVING MACHINE 4 Sheets-Sheet 2 Filed June 16, 1964 I NVE NTOR.

May 3, 1966 SHIGEO ISHIOKA APPARATUS FOR FORWARDING THE WARP IN A WEAVING MACHINE Filed June 16, 1964 4 Sheets-Sheet 5 INVENTOR.

APPARATUS FOR FORWARDING THE WARP IN A WEAVING MACHINE Filed June 16, 1964 May 3, 1966 SHIGEO lSHlOKA 4 Sheets-Sheet 4.

INVENTOR.

This invention relates to an apparatus for braking a rotating body, and more particularly to a warp let-off apparatus for a weaving machine. 7

It is an object of the invention to provide a warp let-off apparatus in which the warp tension is precisely controlled.

It is another object of the invention to provide such an apparatus in which the braking force is applied in such a manner as to maintain a substantially constant tensile stress in the warp.

Other objects of this invention and the advantages thereof will become readily apparent from the following detailed description of the appended drawing in which:

FIG. 1 is a front-elevational sectional view of a warp let-off apparatus of the invention;

FIG. 2 shows the apparatus of FIG. 1 in section on the line II+II;

- FIG. 3 shows the apparatus in section on the line III1II;

FIG. 4 is a plan view of a detail of the apparatus shown shown in FIG. 5 corresponding to FIG. 4.

In FIGS. 1 to 4, spiral ribs 3 are provided on the outer cylindrical surface of a tube 2 rotatably mounted on a fixed frame 1, and engage corresponding grooves in a coaxial, annular abutment plate 7. A shaft 4 is rotatably f mounted on the frame 1 and the tube 4. It is provided with spline ways '5. The inner end of a spiral spring 6 is fastened to the shaft 4, and the outer end of the spiral spring6 is fastened to the tube 2. A guide rod 9 fixed to the shaft 4 engages a slot 8 in the plate 7. A warp 11 is wound on a warp beam having a shaft 12. A gear '14 mounted on the shaft 12 is secured against rotation by a spline 13. A gear 15 meshing with the gear. 14 is mounted on the shaft 4 and is provided with a key to engage the spline ways 5. A sensing rod 16 is rockably mounted on the shaft 4 and carries a roller 17which moves on the surface of the warp. An adjusting cam 18 is fixed on the rod 16 and a brake wheel 19 is rotatably mounted on the tube 2. A worm Wheel 20 iscoaxially attached to the tube 2, and a worm 21 is rotatably mounted on the brake wheel 19 and engages the worm wheel 20, said worm 21 being provided with a non-illustrated handle for manual- 1y rotating the Worm 21. Each oftwo brake shoes 23 has one end attached by a pivot pin 22 to the frame 1, and other ends of the shoes 23 are connected by a rod 24 carrying a spring 25 which urges the brake shoes 23 into engagement wit-h the brake wheel 19.

A' cam follower roller 27 is provided at one end of United. States Patent 0 3,249,125 Patented May 3, 1966 a bar 26 axially slidable on the frame 1, and is urged against the adjusting cam 18 by a spring 28. A shaft 29 carrying two radial arms 32 is rotatably mounted on the bar 26 and is perpendicular to the latter. A radial stop pin 30 on the bar 26 engages a projection 31 on the shaft- 29. The arms 32 normally are maintained in an upright position substantially corresponding to position PM through the compressive action of spring 25 acting through shoes 23 on the shaped surf-ace of cam 27. A bevel gear 33 is fixed on the shaft 29, and a shaft 34 is coaxially journaled on the bar 26 and is provided with spline ways 35. A bevel gear 36 is fastened to the shaft 34 and meshes with said bevel gear 33. An elliptic brake cam 37 which engages the spline way 35 rotates with the shaft 34, but does not move in the direction of the axis of the shaft 34 when the shaft 34 is moved axially by the cam 18. The rotation of the brake cam 37 causes the brake shoes 23 to be engaged or released by the brake wheel 19. The brake shoes 23 are locked with the brake Wheel 19 until the plate 7 abuttingly engages the arms 32 and rotates the brake cam 37.

The apparatus shown in FIGS. 1 to 4 operates as follows:

When the tube 2 is arrested by the brake shoes and the shaft 4 rotates, and if the strain of the spring 6 is within the range in which Hookes law is valid, then the 'moment generated in the shaft 4 is linearly proportional to the strain in the spiral spring 6. Further, the strain in the spring 6 is linearly proportional to the angle through which the shaft 4 is rotated and the angular displacement of the shaft 4 is linearly proportional to the distance over which the plate 7 is shifted. Since the braking moment acting on the warp beam 10 is linearly proportional to the moment of the shaft 4, the axial position of the plate 7 is indicative of the braking moment acting on the warp beam 10. The position of the plate 7 at zero strain in the spring 6 is shown in FIG. 1 at P the position of the plate 7 at maxim-um strain in the spring 6 is P When the actual position of the plate 7 is P, then the braking moment acting on the Warp beam 10 is linearly proportional to P P.

At the beginning of weaving, the plate 7 is at position P and the braking moment is zero. Under this condition, when the worm 21 is rotated, the worm wheel 20 and the tube 2 rotate to increase the strain of the spiral spring 6. As the warp unwinds and the beam 10 is thereby rotated, the plate 7 moves in the direction toward point P until the plate 7 abuts against the arms 32. As the arms 32 are tilted, the shaft 29, the gears 33, 36 and the brake cam 37 rotate and the brake shoes 23 are ready to release the brake Wheel 19. If the spring constant of the spiral spring 6, the tooth ratio of the gears 14 and 15, and the shape of the cam 18 are selected properly, the tension in the warp now has the desired value, while the warp is being taken up by the non-illustrated wind-up mechanism. Since the tube 2 is being locked to the fixed frame-1 by the brake shoes 23, the tension of the warp increases so the tension of the warp decrease. As the plate 7 is thereby moved toward P the brake cam 37 rotates to lock the brake Wheel 19 and the brake shoes 23 as the plate reaches generally the position P.

Another cycle then starts as described above. The normal position of the arms 32 corresponds to the adjusting point of the apparatus and the braking moment acting on the warp beam is kept substantially at the value corresponding to the adjusting point.

As weaving continues the diameter of the warp decreases. In order to keep the tension of the warp constant, it is necessary to reduce the braking moment in proportion to the decrease in the diameter of the warp. In other words, it is necessary to shift the adjusting point. The bar 26 is shifted to theright, as viewed in FIG. 1, by the spring 28 as the diameter of the warp decreases and as the cam 18 is moved accordingly by the rod 16. The arms 32 also shift, so that the braking moment acting on the warp beam is reduced. If the shape of the cam 18 is properly chosen, the tension of the warp can be kept substantially constant regardless of the diameter of the warp;

If the range between the maximum value and the minimum value of the warp tension is to be narrow, the friction between the brake cam 37 and the brake shoes 23 I should be low. The effects of friction may be avoided by providing electrical contacts on the arms 32 and the plate 7 in circuit with an electromagnetic clutch thereby to lock or release the brake shoes 23 and the brake wheel 19.

If the warp tension is to be changed to suit the characteristics of the warp, the spiral spring 6 may be changed, or the gear ratio of the gears 14 and 15 may be adjusted, or the shape of the cam 18 may be changed. It is possible to provide electrical contacts on the stop and the projection 31 which actuate an alarm in order to prevent formation of an uneven weave due to a defect in the warp let-off apparatus.

In the embodiment shown in FIGS. 5 to 8,. the elements 1 to 28 are identical withthe corresponding elements shown in FIGS. 1 to 4, and operate in the same manner. As best seen in FIGS. 5 to 8, a support threadedly engages the bar 26 which is rotatably mounted on the frame 1. Rotation of the bar 26 causes the support 46 to move in the direction of the axis of the bar 26 but does not rotate the cam follower 27. A lock nut 41 prevents the bar 26 from rotating in the support 40 during weaving. The shaft 29 is rotatably mounted on the support 40 and shift-s in slots 39 provided in the frame 1 during axial movement of the bar 26. Two arms 32 are fastened to the shaft 29 and a roller 42 is mounted on the free end of each arm 32 for engagement with the plate 7. A wheel 44 is rotatably' mounted at the free end of a radial arm 43 fixed on the shaft 29. A shaft 45 is rotatably mounted on the frame 1. A plate 46 is fastened to the shaft 45 substantially in axial plane, and the wheel 44 engages the plate 46. A brake cam 37 is attached to the shaft 45, and the rotation of the brake cam 37 causes the brake shoes 23 to lock or to release the brake wheel 19. More particularly, unless the plate 7 contacts the rollers 42, the brake shoes 23 lock the brake wheel 19, and after the plate 7 engages the rollers 42, the plate 7 tilts the arms 32 about the axis of the shaft 29 and thereby causes the plate 46 to pivot the shaft 45 so that the brake shoes 23 release the brake wheel 19. Arms 32 are retained in the desired upright position in the manner described in the embodiment shown in FIGS. 1-4.

The position of the plate 7 in the embodiment shown in FIGS. 5 to 8, as in FIGS. 1 to 4 is indicative of the braking moment acting on the warp beam. As described above with reference to FIGS. 1 to 4, the warp tension can be held constant. If the brake shoes 23 are worn down, the warp tension increases, and it is necessary to compensate for the wear of the. brake shoes 23 when it becomes significant. Since the bar 26 threadedly engages the support 40, compensation can be accomplished by rotating the bar 26 after loosening the lock nut 41.

The apparatus of this invention is useful not only for keeping warp tension constant but alsofor paying out a thread (such as nets for fishing or metallic wire) under a constant braking force. When the apparatus is used to prevent a thread from breaking it is unnecessary to provide a mechanism for shifting the adjusting point. This is accomplished by removing the roller 17, rod 16, adjusting cam 18 and cam follower 27 and by fixing the bar 26 in a suitable position.

The apparatus may be used as a dynamometer if the shaft of the warp beam is replaced by the shaft of a rotary machine, such as an induction motor, and the rod 16, adjusting cam 18 and cam follower 26 are removed and the bar 26 is shifted manually. The induction motor, modified as stated above, delivers a torque which is indicated by the position of the. plate 7, and the torque can be easily adjusted by shifting the bar 26. Under these conditions, the apparatus of the invention operates as an absorption dynamometer.

While preferred embodiments of the present invention have been disclosed, it is to be understood that the scope of the present invention is not limited to the examples chosen for the purpose of the disclosure, but is defined by the appended claims.

What is claimed is:

1. A warp let-off apparatus comprising, in combination:

(a) a warp beam adapted to have warp wound there- (b) brake means for generating a warp beam braking force;

(c) a yieldably resilient member operatively interposed between said brake means and said warp beam for transmitting said braking force, to said warp beam in such a manner that said member is strained by the transmitted force;

(d) braking moment indicating means responsive to the strain in said resilient member for indicating said transmittedforce;

(e) adjusting means responsive to a force greater than a predetermined force as indicated by said indicating means for releasing said braking force, and for reapplying said braking force in response to an indication by said indicating means of a force smaller than said predetermined force; and

(f) shifting means for shifting the point of indication and thereby the magnitude of said predetermined force in response to a dimension of warp wound on said beam.

2. An apparatus as set forth in claim 1, wherein said yieldably resilient member is a spring having one end secured to means rotated by said warp beam for rotation therewith, and another, end secured to said brake means.

3. An apparatus of the type described comprising, in combination:

(a) a rotatable shaft;

(b) brake means for generating a shaft braking force;

('0) a yieldably resilient member operatively interposed between said brake means and said shaft for transmitting said braking force to said shaft in such a manner that the resilient member is strained by the transmitted force;

((1) braking moment indicating means responsive to the strain in said resilient member for indicating said transmitted force; and

(e) adjusting means responsive to a force greater than i a predetermined force as indicated by said indicating means for releasing said braking force, and for reapplying said braking force in response to an indication by said indicating means of a force smaller than said predetermined force. I 4. An' apparatus as set forth in claim 3, further com- 5 6 prising means for shifting the point of indication and FOREIGN PATENTS thereby the magnitude of said predetermined force. 532,217 11/1921 Franm 725,439 2/1932 France.

References Cited by the Examiner 249,729 4/ 1926 Great Britain.

UNITED STATES PATENTS 5 659,205 10/1900 Bryan 1391 DONALD W. PARKER, Primary Examiner. 993,963 5/1911 David 139109 2 253,723 3 1941 s ho f ld 139. .1()() H. S. JAUDON, Assistant Examiner. 

3. AN APPARATUS OF THE TYPE DESCRIBED COMPRISING, IN COMBINATION: (A) A ROTATABLE SHAFT; (B) BRAKE MEANS FOR GENERATING A SHAFT BRAKING FORCE; (C) A YIELDABLY RESILIENT MEMBER OPERATIVELY INTERPOSED BETWEEN SAID BRAKE MEANS AND SAID SHAFT FOR TRANSMITTING SAID BRAKING FORCE TO SAID SHAFT IN SUCH A MANNER THAT THE RESILIENT MEMBER IS STRAINED BY THE TRANSMITTED FORCE; (D) BRAKING MOMENT INDICATING MEANS RESPONSIVE TO THE STRAIN IN SAID RESILIENT MEMBER FOR INDICATING SAID TRANSMITTED FORCE; AND 